More than likely would be a niche feature but the wife loves listening to her radio on the TV as it is hooked up to the sound system. It would be a cool feature if you could have the radio playing but watch another channel at the same time?
Sort of like PIP (picture in picture), because most channels I have use closed captions/subtitles it would keep us both happy.
How I would imagine it would work:
Start watching a radio channel > enter PIP mode which leads back to the guide > enter another channel to watch > channelsdvr asks whether or not to switch to that channel or to overlay it on top of the current playing channel (which is the radio) > channels loads the next channel but mutes the audio of the channel it is loading up.
End result: Radio channel is playing in the background whilst able to watch another channel simultaneously. Obviously would only work correctly if the channel you start to watch has closed captions unless you can lip read.